Holding your arms out for balance, you thrust a hoofed leg around yourself to land in front of you. You do it again, getting even closer to Lyra and her pile of urine. You smell it more clearly now. You still smell FEMALE. But more importantly, you also smell ATTRACTED-FEMALE. You give a loud bray and then hear Lyra interrupt.
"What's going on with you?!" she demands. "SNAP OUT OF IT!!"
You shake your head and look at her, trying to think thoughts but still smelling The Scent. You finally get yourself to talk again.
"You think, you think I'm sexy," you manage.
She scoffs, "Don't flatter yourself," but she can't hide it. The Scent is in you now. Your dick is pounding. The silence is lingering. She sighs. The silence is broken: "Okay, so maybe I do find you a bit ... endearing ... but I ... but I ... I, um ..."
Her voice trails off. You tell her what The Scent has told you: "You want me. You need me. And now I need you."
Lyra gulps at your words. She calls your name. She stumbles forward on her hooves. You catch her in your arms. You waste no time kissing, rubbing up and down each other's shoulders, each other's torsos. She drinks in Your Scent. You do the same to her. But all this making out is not enough. You both need something more than what humans call sex. Something more urgent than what they call love. You and Lyra need to MATE. You and Lyra need to BREED.
She drops to the floor and moans. More pee drips out beneath her. You lick her pussy, and she brays. You stop trying to stand on your donkey legs and hug her from behind, trusting your full weight to her butt and her back. You can't wait to get your painfully erect member inside her. When you finally do, your lustful act does not take very long. Your seed is surging into her, you're both screaming and then braying in ecstasy, and then at last you tumble out of her, dizzy and still dripping semen from your softening cock.
"What did --- what did we just do?" she asks, panting, just as dazzled and out-of-breath as you are.
"I ... I couldn't control myself, Lyra. ... What's ... What's happening to us?"
"What's happening is that I might be prego now, you crazy sex manic. ... But I .... I felt it too, I --- OH!"
The sudden interruption in her speech is apparently a sudden earthquake through her spine, or at least, that's what you feel immediately afterward. "Oooo, Lyra, something's feeling, something's feeling weird Lyra!!!"
"I know HAAAW now should your trap!"
Another jolt through your spine has you clutching your torso, then flopping forward, and then pushing out your arms to try to catch yourself on all fours. Something's happening and now--POP!--something has snapped loose inside your pelvis, just above your ass!
"Damn, my tailbone feels wobbly," says Lyra, either to you or to yourself, you aren't sure. But a pressure starts building in your lower back, prompting you to squeeze your eyes shut and raise your butt high into the air as though you could somehow force it out.
Slowly but surely, the pressure seeps out, but as your backbone feels less pent up inside your torso, it also feels more weighted down by something out behind you. You feel something soft and brush-like tickle your ankle (your hock), causing you to snap your eyes open and look back between your legs.
"What the hell?!" you scream as you instantly notice what's back there: a thick, noodle-like cord of something that looks like your own flesh, with a lengthening tuft of what looks like your own hair at the tip of it. A spasm of muscle movement strikes then end of your spine, and what's hanging behind you flits out to your left and flops back down again. You gasp and reflexively try reaching back, but your on all fours, so you immediately fall forward and land hard on your chest. At least you can look forward and see Lyra, who is standing up on her altered legs and holding what looks like her own skinny, tasseled tail in her hands. She stammers, "no, NO! Get it OFF!" before she yanks the thing, brays in pain, and has to let go of it. Standing is hard when you have a donkey's hind legs instead of your human legs, so you just focusing on getting your arms underneath you again and looking back at your new appendage like before. It's hanging limply at first, but you've seen that you can move it. You swish its length a couple times and even slap your hip with it.
"This is all my fault, Lyra!" -- you call out -- "We fucked like animals, and we're tailed like animals!"
"Shutupshutup SHUT UP!" she yells back. "We've got to get out of here, we've got to figure out what's happening to us, we've got to--"
Your and Lyra's ears suddenly twist toward a creaking sound that must be coming from the barn door. You both freeze stiff and silent, wondering if you're about to get at least a partial answer to all this.